(546f) PEM Electrolyzer for the Hybrid Copper-Chlorine Cycle for Hydrogen Production

High efficiency, friendly to the environment and low cost are key criteria for the designing of large scale production of hydrogen. Thermo-chemical cycle methods essentially split water indirectly via a series of chemical reactions. So, in these processes, not only pure hydrogen with zero carbon species emissions are produced but also, recovering heat from the nuclear reactor, overall efficiency could be higher than conventional reforming processes [1, 2].

Copper-chlorine [3-5] is a novel thermo-chemical cycle with the advantages of mild operating conditions and able to recover low-grade heat from nuclear reactors. Three basic reactions are involved in this cycle: hydrogen is produced by electrolysis of cuprous chloride in membrane reactor; oxygen is produced by thermolysis of copper oxychloride and hydrolysis of cupric chloride into copper oxychloride.

In this presentation, we demonstrate electrolysis of cuprous chloride in a Nafion membrane reactor. To quantify the individual voltage loss in the total polarization curve, the half cell cuprous oxidation reaction (COR) is studied on the rotating disk electrode. From the Levich?Koutecky equation, the kinetic current is separated from mass transfer. The kinetic current is used to quantify the anode overpotential and voltage loss in mass transfer. The mass transfer voltage loss and anode overpotential are identified to be the limiting factors to the electrolyser performance, both of which contribute about 200 mV at the current density of 100 mA/cm2. Also, kinetics current shows a weak dependence of COR on conventional electrochemical catalysts such as Pt black, Pt/C, RuO2 and Vulcan XC 72R. Use of porous electrode will be proposed to improve the mass transfer effects.

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[3] R. Zhang, J. W. Weidner, ECS Trans. 19, 95 (2009).

[4] G. F. Naterer, M. Fowler, J. Cotton, et al, International Journal of Hydrogen Energy, 33, 6456 (2008).

[5] Y. Gong, E. Chalkova, N. N. Akinfiev, V. Balashov, M. Fedkin, and S. N. Lvov. ECS Trans. 19, 21 (2009).